Sluice box riffle



Dec. 12, 1939. P E M 2,183,157

SLUICE BOX RIFFLE Filed June 29, 1937 2 Sheets-Sheet l INVENTOR 6. Gwen man 4 ATTORNEY Dec. 12, 1939. P. SWEDMAN SLUICE BOX RIFFLE 2 Sheets-Sheet 2 INVENTOR. Pang Jrveaman Filed June 29. 1937 ATTORNEY Patented Dec. 12, 1939 in'r OFFICE SLUIC E BOX RIFFLE Perry Swedman, Seattle, Wash. Application June 29, 1937, Serial No. 150,9'72

6 Claims.

My invention relates to a sluice box riflie. More particularly, my invention. relates to a riffie. to be positioned in the bottom of a sluice box to be used in mining operations for the purpose of separating precious metals from material which is lighter than said metals.

Such sluice boxes are commonly used in placer mining for gold, platinum and such like precious metals. Although I am herein describing my 10 invention as particularly applied. to placer mining for gold for purposes of definiteness and clearness, yet it is to be expressly understood that the invention is not to be limited to any such specific use, but is applicable to all uses where like conditions or problems exist in whole or in part, so far .as the invention is applicable. Of course, the invention is applicable to the separation of bodies which diifer'in weight, even though they are not precious metals.

,It is common practice to employ wooden riffles, but these wear out very rapidly and are objectionable in that rocks catch between adja cent rifiie bars and in freeing them often the rifiles are seriously damaged. It will be understood that gravel, including rocks of varying size, isyrun over the rifiies in the sluice boxes and imposes a very. severe wearing and grinding action upon the rifl'les. Attempts to overcome the objections to wooden rifiles have'been made by forming the rifiies of metal, such as iron. But these soon-wear and develop sharp edges, and become very difiicult to handle. at the time of .cleaning upthe' boxes, 1. e., at the time when theriflles are raised to collect the gold. or other valuable minerals which have been deposited between the rifiles.

A primary object of my invention is to provide a rifile of which the wearing surface is formed of rubber. ,f

40 Another primary object of my invention is to provide a rifile which is formed of two partsa. metal frame of bars and rubber elements adapted to be readily replaceable and releasablysecured to said bars.

A further primary object of my invention is to provide a rifile which is highly resistant to the grinding and abrasive action of gravel, which will-have a life a plurality of times longer than the wood and metal riffles heretofore in use, and

whichwill not be seriously damaged by the removal of rocks which have lodged between adjacent rifile bars. I 3

.Alsoit .is primary object of my invention to provide a rifile which will have a relatively large space in which concentrates may collect, and

which space may operate more efiectively as a pocket which protects the metal concentrates against packing by the heavy stream of gravel passing thereover.

A further primary object of my invention is to'ha-ve such wearing part formed of rubber, the elasticity of which, together with itsform and with its manner of mounting, results in developing vibrations under the action ofthe stream of gravel passing thereover. 'The vibrating is part0 ticularly effective in causing fine gold particles to precipitate and collect behind said nifiles.

A still further, primary. object ofmy invention is to provide a riffle which is economical in first cost and in maintenance, and which is char- 15 acterized bybeing light in weight, as such riffles are often used in connection with dredges which are floatingly mounted, since it may be necessary to provide some eight hundred to one thousand of theyrifile frames. embodying my in- 20 vention, which are preferably thirteen inches wide, and whichare, of course, .of the usual length to correspond with the width of :the sluice whiohis about thirtypinches as. commonly employed in sluice boxes for .dredges. small 25 dredges the widthof the sluice boxes maybe eighteen or twenty inches. The frames are preferably of aluminum.

A still further. object .of mycinvention is to provide a rifile of a character which ismmpress- 30 ible and which will permit a Wedging rock .to be driven through the rifile without injury to the riille.

A .still further object oithe invention is to provide rifile means comprising a frame of rela- 35 tively strong and substantial material provided with cross bars, having readily appli'cableand readilydetachable wear resistant resilient elements or caps of rubber or like material provided on the upper portions thereof, over which 40 caps the sand and gravel pass.

' The above mentioned general objects of.my invention, together with others inherent in the same, are attained by the device illustrated in the following drawings, the same being preferred exemplary forms of embodiment ,of ,.my

invention, throughout which drawings like referencenumerais indicate like parts:

Figure l is a plan view of ya r-iflleisection con 50 structed in accordance with this invention;

Fig. 2 is, a view partly in section-and partly in elevation of the same taken substantially zon dotted line 2-2 of Figure l;

Fig. 3 isa transverse section onan enlarged 55 scale taken substantially on dotted line 33 of Figure 1, parts being shown in elevation;

Fig. 4 is a fragmentary detached perspective view of a portion of a rifle frame, parts being shown in section;

Fig. 5 is a fragmentary detached perspective View, with parts in section, of a rubber cap member as the same may appear when removed from the bars of the rifle frame;

Fig. 6 is a plan View of a modified form of riffie means constructed in accordance with this invention;

Fig. 7 is a sectional view on a larger scale, with parts in elevation, taken substantially on broken line '!'i of Fig. 6;

Fig. 8 is a detached perspective view of a fragment of the frame member of the rifle device shown in Fig, 6;

Fig. 9 is a detached fragmentary perspective view of a piece of one of the rubber cap members used in the embodiment of the invention shown in Figs. 6, 7 and 8;

Fig. 10 is a view in cross section of a modified form of a rubber cap embodying my invention; and

Fig. 11 is a view in cross section of a still further modified form of a rubber cap and rib of the metal frame embodying my invention.

Figs. 1 to 5, inclusive, show a preferred embodiment of the invention comprising a frame formed of two substantially parallel spaced apart side bars l6 and H and a plurality of substantially parallel transverse rifle bars H2. The side bars [0 and H are preferably of inverted L shape in cross section, as shown in Figs. 2 and 4. The rifle bars 42 have their end portions rigidly connected with the side bars, as by forming them integral with said side bars. These rifle bars l2 are preferably of substantially T shaped cross section with upright web portions which are narrow at their bottom edges and wider where they merge with the top flanges or head portions of the rifle bars. The under sides of the head portions of the rifle bars are preferably formed with upwardly concaved portions 63, which are hook shaped in cross section. The upper sides of the top flanges of the rifle bars [2 are preferably inclined, as shown in Figs. 3 and 4 and said upper sides are positioned below the plane common to the uppermost portions of the upper flanges of the side bars ID and II.

The rubber caps, elements or members I 2, which are adapted to fit over the rifle bars l2 are each of rectangular cross section. The upper face portion I5 has downwardly extending side walls it, which terminate in two depending gripping side flanges I? that are separate from each other so as to leave the rubber cap member open along the bottom throughout its entire length. Passageways 23, corresponding in shape to the head portions of the riifle bars, extend throughout the length of the cap members and internal bead portions I9 are provided to engage within the hook shaped concave recesses l3 underneath the top flanges of the rifle bars 12. The rubber cap members are placed on the rifle bars l2 by spreading the flange portions I1 and side walls I6 apart and pressing the cap members over the top flanges of the rifle bars [2. The depending flanges ll of the cap members fit closely against the upright web portions of the rifle bars l2. These flanges H are relatively thin and do not retard the vibration of the cap members and leave ample room between adjacent rifle bars for the collection of values.

The passageways l8 in the rubber cap members are preferably slightly larger than the head portions of the rifle bars l2 and fit somewhat loosely thereon so that the cap members are free to vibrate a limited amount as water and mineral bearing sand and gravel are passed over the cap members. It is found that this vibration of the cap members assists in the separation or precipitation of the gold and heavier minerals from the lighter sands and gravels. It will be understood that the passageway or recess I8 in the cap l4 may be of a size to render the cap tightly fitting to the bar i2. However, by providing the passageway slightly larger, a

vibratory movement is permitted under the impact of the gravel striking the face or top portion l5 of the cap. It will be noted that the flanges ll pinch inwardly. This inward pinching applies a pressure on the inclined face of the portion of the bar l2, and accordingly tends to support the caps I l and permits a twisting or rocking movement under impact of the gravel passing thereover. This movement combines with the movement arising from the resiliency of the rubber to augment the vibratory movement of the cap as a whole.

These details relative to the passageway l8 being larger than the corresponding portions 52 of the bar over which the cap is to be placed this pinching action of the flanges H are parts of my invention which are important and are provided in the preferred form. However, much of the advantage of my invention may be obtained without these features.

If the rubber cap I4 is provided with a passageway I8, which precisely fits the T part of the bar l2, and no pinching on inclined planes is provided by the flanges l'i', still very important advantages of my invention remain. The mere resiliency of the rubber will provide for considerable vibration under the impact of the gravel and the long wearing quality of the rubber cap and the economy incident to its long wearing and ready replaceability and the forming of the riffie in two parts, via, a metallic frame of light metal and replaceable rubber cap for the bars,still form important parts of my invention.

The water, together with the sand and gravel, pass over the rifles in the direction indicated by the arrows in Fig. 3. This flowing material is thus caused to cascade and eddy slightly and move in a downward direction as it passes off of the higher edge of each rifle cap and the heavier particles will continue this downward movement due to their greater inertia and will settle into the spaces between the rifle bars.

The rifle devices are made up in sections of convenient shape and size to be handled. These sections are usually placed in the bottom of a sluice box, not shown, and secured in any suitable manner. Any desired number of sections are used to secure the desired over-all length of rifle. The dimensions of the individual rifle bars and distance between bars may be varied. Satisfactory results have been obtained by making the cap members of from one to one and onehalf inches across the top and by having spaces of from one to one and one-half inches between adjacent cap members.

sand and gravel. The cap members are not costly and are very easy to replace in the event they do become worn. The metal frames are not subject to abrasion and will last practically indefinitely.

These cap members are F very durable and highly resistant to abrasion by remote from transportation facilities so that it v It will be remembered that mining operations are often carried on in sections of the country becomes amatter of great importance to provide elements of the operating equipment in a form which may be readily replaceable and thereby avoid reconstructing. The relatively light rubber caps or'elements are not only strongly resistant to wear, so that they have a life a plurality of times longer than any other rifle commonly employed heretofore, but they are formed of material'relatively light in weight so that maintaining them in their proper form for full operating efficie'ncy is rendered comparatively simple and economical.

The cap members are elastic and stones which wedge between adjacent cap members can be displaced easily without damage to the rifles. Such stones may be readily driven downward as the side walls I t are compressible and as the stone passes beyond these walls the opening diverges until the bars l2 are contacted. If they are not wedged in between the walls 16 of adjacently disposed rubber caps, then, of course, the stones may be lifted upwardly so that in either case they are readily removed without injury to the rifle bars.

The modified construction shown in Figs. 6 to 9 embodies an integral frame comprising spaced apart rifle bars 20 .of approximately T shape in cross section. The lower sides 22 of the head portions of the rifle bars 20 and connector bars 2| are inclined upwardly from the outside toward medial planes of said bars to provide hook like means for engagement with inwardly directed bead portions 23 of rubber cap members 24. The rubber cap members 24 have longitudinal passageways 25 shaped to fit over the head flanges of the rifle bars 20 and also have transverse passageways 26 shaped to fit over the head flanges of the connector bars 2! The tops of the rifle bars 20 are not inclined but the tops of the cap members 24 may be inclined to obtain the same effect as hereinbefore explained in connection with the cap members shown in Figs. 1 to 5. The rubber cap members 24 are releasably secured and replaceable upon the bars 20 and the rifle device shown in Figs. 6 to 9 operates in substantially the same manner as the device shown in Figs. 1 to 5.

Bars 2! have thereon short cap members 24'.

The modified construction shown in Fig. 10 illustrates a difierent form of flange 21.

The modified construction shown in Fig. 11 shows a still further form of; cap 28 which is held upon the modified form of rifle bar 29'by screw means 30 in a countersunk recess 3| in the cap 28. I have discovered that it is important that the flanges 32 of cap 28 extend for a part of the distance down the bar 29. The eddying water, with its sand and gravel, causes a severe wearing along the upper portions .of the bar 29 so that protection is necessary.

Obviously, changes may be made in the forms, dimensions and arrangement of the parts of my invention, without departing from the principle thereof, the above setting forth only preferred forms of embodiment. I claim: 1. A rifle comprisinga metal frame member having cross bars of a T form in cross section;

and a resilient, rubber cap member having a recess of a T form cross sectionally considered engageable with said cross bars.

2. Rifle means of the class described, comprising spaced apart rifle bars; and resilient rubber cap members removably secured to said rifle bars-said cap members covering the upper psortions of said rifle bars and providing an opening therebetween with diverging sides, whereby rocks over and releasably receiving the enlarged upper edge portions'of said rifle bars providing. readily renewable abrasive resistant caps for said rifle bars.

4. Rifle means of the class described, comprising spacedapart normally horizontal rifle bars having upper edgeportions of enlarged cross section; and resilient rubber cap members extending substantially throughout the lengthlof said rifle bars, said cap members having longitudinally extending internal recesses open along one side of the cap members and fitting over and receiving the enlarged upper edge portions of the bars, the

side walls of the cap members being flexible whereby the cap members will vibrate on the rifle bars when material and water is passedthereover, said recesses being larger than the enlarged upper edge portions of the bars whereby said cap members will vibrate on the rifle bars when material is passed thereover.

5. Rifle means of the class described, comprising spaced apart normally horizontal rifle bars of substantially T shaped cross section having 1 upper head flanges which are undercut on their lower sides providing. portions of substantially hook shaped cross section; and resilient rubber cap members having longitudinally extending internal recesses open along one side of the cap members and corresponding in shape to the head portions of said" T shaped rifle bars, said cap members having head portions engaging beneath the hook shaped portions of said rifle bars removably securing the cap members to the rifle bars.

6. Rifle means of the classwdescribed, comprising spaced apart normally horizontal rifle bars having upper edge portions of enlarged cross section; and resilient rubber cap members having longitudinally extending internal recesses fitting over and releasably receiving theenlarged upper edge portions of said rifle bars providing readily renewable abrasive resistant caps for said rifle bars, and having depending side flanges which pinchingly hold the cap to said bars.

PERRY SWEDMAN. 

